package cn.lastcc.pwdmanage.core;

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

/**
 * AES 加密解密工具类
 * 
 * @author Added by baidongyang 2013-6-23
 *
 */
public class AesUtil {

    private static final String ALGORITHM = "AES";

    /**
     * 加密
     * 
     * @param content 需要加密的内容
     * @param password  加密密码
     * @return
     * @see http://blog.csdn.net/hbcui1984/article/details/5201247
     */
    public static byte[] encrypt(String content, String password) {
            try {
		    SecretKeySpec key = setSecretKey(password.getBytes());
                    Cipher cipher = Cipher.getInstance(ALGORITHM);// 创建密码器
                    byte[] byteContent = content.getBytes("utf-8");
                    cipher.init(Cipher.ENCRYPT_MODE, key);// 初始化
                    byte[] result = cipher.doFinal(byteContent); // 加密
                    return result;
            } catch (NoSuchAlgorithmException e) {
                    e.printStackTrace();
            } catch (NoSuchPaddingException e) {
                    e.printStackTrace();
            } catch (InvalidKeyException e) {
                    e.printStackTrace();
            } catch (UnsupportedEncodingException e) {
                    e.printStackTrace();
            } catch (IllegalBlockSizeException e) {
                    e.printStackTrace();
            } catch (BadPaddingException e) {
                    e.printStackTrace();
            }
            return null;
    }

    /**解密
     * @param content  待解密内容
     * @param password 解密密钥
     * @return
     * @see http://blog.csdn.net/hbcui1984/article/details/5201247
     */
    public static byte[] decrypt(byte[] content, String password) {
            try {
                    SecretKeySpec key = setSecretKey(password.getBytes());
                    Cipher cipher = Cipher.getInstance(ALGORITHM);// 创建密码器
                    cipher.init(Cipher.DECRYPT_MODE, key);// 初始化
                    byte[] result = cipher.doFinal(content); // 解密
                    return result;
            } catch (NoSuchAlgorithmException e) {
                    e.printStackTrace();
            } catch (NoSuchPaddingException e) {
                    e.printStackTrace();
            } catch (InvalidKeyException e) {
                    e.printStackTrace();
            } catch (IllegalBlockSizeException e) {
                    e.printStackTrace();
            } catch (BadPaddingException e) {
                    e.printStackTrace();
            }
            return null;
    }

    /**
     * 将二进制转换成16进制
     * @param buf
     * @return
     * @see http://blog.csdn.net/hbcui1984/article/details/5201247
     */
    public static String parseByte2HexStr(byte buf[]) {
            StringBuffer sb = new StringBuffer();
            for (int i = 0; i < buf.length; i++) {
                    String hex = Integer.toHexString(buf[i] & 0xFF);
                    if (hex.length() == 1) {
                            hex = '0' + hex;
                    }
                    sb.append(hex.toUpperCase());
            }
            return sb.toString();
    }

    /**
     * 将16进制转换为二进制
     * @param hexStr
     * @return
     * @see http://blog.csdn.net/hbcui1984/article/details/5201247
     */
    public static byte[] parseHexStr2Byte(String hexStr) {
            if (hexStr.length() < 1)
                    return null;
            byte[] result = new byte[hexStr.length()/2];
            for (int i = 0;i< hexStr.length()/2; i++) {
                    int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);
                    int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);
                    result[i] = (byte) (high * 16 + low);
            }
            return result;
    }

    /**
     * 获得Key
     * @param password
     * @return
     * @see http://my.eoe.cn/elvnxuan/archive/2160.html
     */
    public static SecretKeySpec setSecretKey(byte [] password) {
        SecretKeySpec key = null;
        try {
            KeyGenerator kgen = KeyGenerator.getInstance(ALGORITHM);
            SecureRandom sr = null;
            if (android.os.Build.VERSION.SDK_INT >= 10) {
                sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");
            } else {
                sr = SecureRandom.getInstance("SHA1PRNG");
            }
            sr.setSeed(password);
            kgen.init(128, sr);
            SecretKey secretKey = kgen.generateKey();
            byte[] enCodeFormat = secretKey.getEncoded();
            key = new SecretKeySpec(enCodeFormat, ALGORITHM);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchProviderException e) {
            e.printStackTrace();
        }
        return key;
    }
}
